Difference bw urdf and sdf

In TF course there is no detail of “sdf” is given, which tags used in sdf? difference between in urdf and sdf?


SDFs are not explained just because normally when we work with ros, is URDF/XACRO the format used. SDFs normally are used for non ros objects in the Gazebo simulation, like walls, people and objects. Robots normally are defined in URDF XACRO, because it has better integration with ROS systems.

okay…one thing i want to as, normally we have files with exension .urdf or .xacro. but there are some files with extension .urdf.xacro, what it means? they have properties of both?

XACRO is an extension of URDF to do MACROS, this means, it allows to define block of URDF code and then paste that code in several places of the main URDF. For example, imagine you want to create a robot with four legs. Then you can define a XACRO MACRO called leg that contains the URDF code of a leg. Then, inside the URDF of your robot, you call that XACRO MACRO 4 times, so you avoid having to write 4 times the same code.

All that is explained in the URDF for Robot Modeling course.

ok thanks, its clear now